AC current sensing probes are typically used to measure AC current flowing through a conductor on a device-under-test (DUT). Such current sensing probes can be broadly classified into two categories—passive current sensing probes that do not require a power source for operation and active current sensing probes that include circuitry requiring a power source to operate. Passive current sensing probes generally suffer from bandwidth issues and can only be used to measure AC currents having a limited range of frequencies. Consequently, some passive current sensing probes have been equipped with frequency compensating elements such as inductors and capacitors that boost signal amplitudes at either a low end of a frequency band of operation or at a high end of the frequency band of operation. However, this approach generally provides a very limited amount of improvement in frequency response. Additionally, some passive current sensing probes can disturb and/or modify the AC current flow in a current-carrying conductor when connected to the current-carrying conductor for purposes of current measurement, thereby leading to inaccurate results. This issue is particularly problematic when the AC current frequency is high and thus more susceptible to disturbance.
Active current sensing probes address some of the limitations inherent in passive current sensing probes. However, many conventional active current sensing probes still suffer from frequency bandwidth limitations, often as a result of impedance mismatch issues between the probes and the DUT. The impedance mismatch issue can lead to an insertion loss that is manifested as an undesirable amount of current being drawn by the current sensing probe from a current-carrying conductor in the DUT, thereby modifying the current flow in the DUT and providing an erroneous current measurement. Consequently, in some conventional cases, a sensitivity parameter of an active current sensing probe is undesirably sacrificed in order to minimize insertion loss.